What is the current situation of the published N-of-1 trial?

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Presenting author

Kehu Yang

Contact person

Kehu Yang

Abstract text

Background:
An N-of-1 trial is a clinical trial in which a single patient is the entire trial, a single case study. It can be very effective in confirming causality. This can be achieved in many ways. However, there is no clear the epidemic characteristics of N-of-1 trial.
Objectives:
To survey the current situation of N-of-1 trial and provide related information on published year, author, country, journal, annual citation information, the type of literature of N-of-1 trial.
Methods:
An electronic literature search of all N-of-1 trial from inception to Feb 2013 was conducted using Web of Science. Using the following search terms “randomized controlled trial in individual patient, single case experiment, N-of-1 trial, N-of-1 RCT, N-of-1 study” in the title or keyword. Two reviewers independently determined study eligibility and extracted details on published year, author, country, journal, annual citation information, the type of literature. Disagreements were resolved by the third author.
Results:
111 studies were included, table showed that the frequency and of citations of N-of-1 trial in each year, published studies in different country and type of literature; one journal published four N-of-1 trials, two journals published three N-of-1 trials, nine journals published two N-of-1 trials, 83 journals only published one N-of-1 trial; top six research areas were as follows: 19.82% N-of-1 trials focused on neurosciences neurology, 14.41% for psychology, 13.51% for general internal medicine, 10.81% for pharmacology pharmacy, 9.01% for rehabilitation, 7.21% for health care sciences services; As well as, 365 authors wrote 111 papers, the average citations per paper was 11.25,average citations per year was 46.26,the h-index was 19.
Conclusions:
More and more N-of-1 trials are published in different journals and focus on different research areas, which methodology is still in the development stages. Therefore, undertake further research to increase methodological transparency, develop reporting standards, and report the methodological limitations of N-of-1 trials.